LONDON (AP) -- Thousands of demonstrators are gathering under sunny skies in central London to protest plans for Britain to withdraw from the European Union.
The Unite for Europe march included many carrying EU flags just days before Britain is expected to begin its formal divorce from the EU.
Prime Minister Theresa May plans to trigger Article 50 Wednesday, setting the process in motion. Negotiations are expected to take at least two years.
The substantial march follows by three days an attack on Parliament. Organizers considered delaying the march but decided to go ahead.
Organizers said in a statement that "we will not be intimidated. We will stand in unity and solidarity."
Britain voted in a June 23 referendum to leave the EU.